1. Field of the Invention
The present invention relates to a Subscriber Identification Module (SIM) card used in a portable wireless terminal, and in particular, to a SIM card that can be used as an auxiliary power source so that an emergency call can be made even when a main power source is exhausted, and a portable wireless terminal using the same.
2. Description of the Related Art
In general, a Subscriber Identification Module (SIM) card is detachably mounted to a portable wireless terminal based on a European-style Global Positioning System (GPS). Subscriber information and system information of the portable terminal are stored in the SIM card. Advantageously, even when the SIM card is mounted to another portable terminal, the stored information can also be used in that portable terminal. For example, when the SIM card, in which call history, user-set information, system information, and so on are stored, is mounted to a new portable terminal compatible with the SIM card, the new portable terminal can also use the previously stored information. Recently, due to this advantage, a User Identity Module (UIM) card is also widely used in the mobile wireless terminal.
The SIM card has a size of a plate-type flash memory. For electrical connection, the SIM card is inserted into a socket mounted on a card mounting portion. A plurality of contact pads each having a specific size are disposed to one surface of the SIM card, and physically come in contact with their corresponding connectors provided in the socket of the portable terminal. Specifically, the SIM card includes six SIM contact pads, i.e., as known in the art, SIM_GND, SIM_VDD, SIM_IO, SIM_CLK, SIM_RST, and SIM_VCC. These contact pads are electrically connected to the socket of the portable terminal by the use of their corresponding connectors.
Although the wireless mobile terminal has an excellent portability, the wireless mobile terminal cannot be used when a battery is out of power due to its limited capacity. For this reason, in general, a user carries an auxiliary battery pack in addition to a charging-type battery pack mounted to a backside of the portable terminal. If necessary, the user has to recharge the exhausted battery pack by connecting the portable terminal to a power source means.
However, if the battery pack mounted to the portable terminal is exhausted in a situation where the user is in a place where the battery pack cannot be recharged or in an emergency situation (e.g., accident), there is no way to use an emergency call function provided by the portable terminal.